Machine-readable codes have been in use for many years. Such codes are often implemented as optical codes that are read by capturing the reflection of electromagnetic radiation from the code. The ubiquitous one-dimensional barcode is used for product tracking and to automate purchases. For example, one-dimensional barcodes are in widespread use for managing point-of-sale purchase transactions using computer-controlled laser scanners.
More recently, two-dimensional codes, also known as matrix barcodes, such as QR (“Quick Response”) codes, have become popular. Two-dimensional codes can encode a much greater quantity of information than one-dimensional codes. The information encoded in such codes is readily accessed through digital photographs of the codes that are processed by application software found in computers and mobile communication devices such as cell phones having digital signal processing and internet communication access. QR codes are frequently employed in conjunction with product advertising to provide an internet URI website link with information about the product advertised.
Optical bar codes are typically intended to be visually observable by humans, so that humans can find the codes and take appropriate action to access encoded information or otherwise use the codes. In contrast, steganographic information is designed to be hidden within an image. The present invention addresses optical codes that are intended to be observable to humans and does not address steganographic codes.
Referring to FIG. 12, a matrix barcode of the prior art is illustrated with dark and light elements forming black modules on a white background. As used herein, the term matrix barcode is used synonymously with two-dimensional optical code. A QR code is an example of a matrix barcode. Such codes are machine-readable codes 1 and are input by a machine (such as a scanner or digital imager), analyzed with image processing equipment and software, and the information encoded in the code decoded, extracted, and used.
The formation, printing, scanning, and decoding of one- and two-dimensional bar codes is known in the art. For example, U.S. Pat. No. 7,273,175 describes a method, apparatus and a storage medium for locating QR codes. An image processing apparatus including an optical reader and image processing hardware is discussed in U.S. Pat. No. 7,835,037. U.S. Pat. No. 7,841,531 discloses a camera operating system and matrix decoding device. U.S. Patent Application Publication 20090078772 describes techniques for decoding images of barcodes. U.S. Pat. No. 6,229,964 addresses an icon reader that reads picture identification data from a data icon on an image print. U.S. Pat. No. 7,123,782 describes using a code printed in association with a printed image to identify an electronic repository for a digital version of the printed image.
Codes on an image print can include a reference to remotely-stored information. A code reader can scan the code, decode the reference, and retrieve the information. For example, U.S. Pat. No. 6,199,048 describes a system and method for using identification codes found on ordinary articles of commerce to access remote computers on a network. U.S. Patent Application Publication 2004/0096123 discloses a method and system for locating and accessing digitally stored images including a hard copy print, method and system for producing the hard copy print.
These disclosures teach finding and decoding machine-readable codes 1 and accessing information referenced by machine-readable codes 1. Multiple machine-readable codes 1 can be available and reference independent information or choices for selection by a user. However, it can be the case that users are confronted with a variety of interdependent choices, for example a selection of product options or tasks to achieve a desired goal. The simple selection of an option or reference to information will not achieve the desired selection and organization of information choices or elements. They do not address the use of multiple machine-readable codes 1 by users to organize information. There remains a need, therefore, for a system and method for efficiently making an ordered element list using machine-readable codes 1.